2.1.1 microscopes Flashcards
how are cells prepared in a lab (6)
- tissue fixation + processing in formaldehyde
• dehydration of specimens to remove water
• embedding in wax to avoid distortion
• section-cutting using special instrument to make very small, THIN slices (to maximise light that can penetrate)
• staining (add stain at the edge of the slide)
• add coverslip - try to avoid air bubbles.
how do you calculate magnification?
image size / actual size
what is the magnification of a light microscope?
- up to x1500
what is the resolution of a light microscope?
200 nanometres
what is the magnification of a laser scanning confocal microscope?
up to x1500
what is the resolution of a laser scanning confocal microscope?
10 nanometres
what’s the resolution of a scanning electron microscope?
between 0.2 and 10 nanometres
what’s the magnification of the scanning electron microscope?
x15000 to x20000
what type of images are produced by light microscopes?
- 2D images
- coloured images
what type of images are produced by laser scanning microscopes?
- 3D images
- colour
what type of images are made by transmission electron microscopes? (2)
- 2D images
- black and white images
what type of images are created by scanning electron microscopes?
- 3D images
what’s the definition of magnification?
- how many times larger an object is compared to its actual size
what’s the definition of resolution?
- the ability to distinguish two points in close proximity as seperate.
what is the difference between magnification and resolution?
